<?php echo $form->render(); ?>
<div class="admin_product_sizes">
    <span class="title">Chosen sizes</span>
    <div class="product_sizes">
        <br />
        <form id="size_form" method="post" action="/admin/product/ajaxSaveData"> 
            <?php foreach ($sizes as $size): ?>
                <input type="hidden" name="size" value="<?php echo $size['id']; ?>" /> 
                <span id="size-<?php echo $size['id']; ?>" class="size"><?php echo $size['name']; ?></span>
                <div class="sep"></div>
            <?php endforeach; ?>
        </form>
    </div>
    <a href="#" onclick="return false;">Add sizes</a>
</div>